For me I use the following:
Temporary containers - This add-on is so amazing and really helps when signing into multiple accounts
UBlock Origin - Add blocker, probably the best available
Dark Reader - Helps to make the web a little more readable and less harmful to the eyes
The classics: uBlock Origin to block those pesky ads and trackers as well as Dark Reader so I don’t get flashbanged everytime I visit a website that doesn’t have a dark theme
LibRedirect is awesome for avoiding tracking websites and replacing them with alternative FOSS frontends
Bitwarden to manage my passwords
Violentmonkey to load custom Userscripts
Snowflake to support the Tor network